I have a hobby farm with a few different interesting breeds, and I don't even come close to breaking even. It all depends on what your goal is. I don't even attempt to sell day old chicks, because I can't compete with the big hatcheries, and I can't sex my chicks. I have found a local niche where I can sell started pullets and cockerels around 5-7 weeks of age for more money, but it costs more to get them to that point. They sell quickly, so I get a little bump of money at the time, but I cry if I go back and look at the money I have spent to get here. I do it for fun. I love raising chicks, and by the time they are feathered out, I enjoy selling them to people, but I will never cover the coops, pens, brooders, heat lamps, incubators, feeding stations, power, water, etc...
I'm just not set up as a business. You have to decide what your goals are, and go from there. I think anyone selling day olds on a small scale is going to be very lucky to break even